Method and system for welding conduits

ABSTRACT

A method for welding two or more conduits includes aligning end portions thereof in an abutting relationship to define a gap. The method includes performing a spatter free root weld along the gap to configure a root layer while the inner circumferential surface side is unobstructed. After the root weld is complete, an outward thrust is applied along the inner circumferential surfaces of the conduits. During the application of the outward thrust, a filler weld is performed along the gap to fill the gap and to facilitate shrinkage of the filler and root weld materials longitudinally and radially outward while preventing pressing out of the filler and root weld materials radially inward of the inner circumferential surface.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a divisional application of, and claims priority to,U.S. patent application Ser. No. 13/958,825, filed Aug. 5, 2013, whichclaims priority to European Application 12179757.5 filed Aug. 8, 2012,the contents of which are hereby incorporated in its entirety.

TECHNICAL FIELD

The present disclosure relates to welding technology, and, moreparticularly, to a method and a system for welding two or more conduits.

BACKGROUND

Pieces of conduits, such as pipes or tubes, are welded togethercircumferentially to configure a required conduit length for beingutilized in various purposes, including but not limited to, in heatexchangers or as transportation pipe lines, generally, utilized invarious industries for the transportation of the chemicals, mineral oiland natural gases, and the like. Welding the pieces of conduits witheach other requires much care, time and skill so that it isextraordinarily expensive. In welding the pieces of conduits there aregreat chances of deposition of weld material in and around a weldingzone. Deposition of the weld material along the inner surfaces of theconduits may reduce the life of the welded conduits due to corrosionsthat may arise due to particles in the travelling through the weldedconduits. Many attempts have been made to obviate such problems, and arestill being made.

Generally, the welding of such conduit pieces is two steps process. Inthe first step, a base weld, generally known as a root layer, is madebetween the pieces of conduits in a relatively small gap, generallyknown as a root gap, therebetween. Base weld or the root layer is madeat part of wall thickness adjacent to the inner surfaces of the conduitpieces. While forming the root layer there are great chances of the weldmaterial to travel across the inner surfaces and get deposited. However,various modern technology are nowadays available which may prevent thedeposition of the excess weld material, such as providing backing ringsetc., along the welding zone. Such backing rings are provided on theinner surfaces along the root gap as a support, and thereafter the baseweld is conducted. Such backing ring prevents the root weld of the rootlayer to travel across the inner surfaces of the conduit pieces in turnpreventing weld material deposition thereon. Since the backing ring ispartially melted, it has to be removed afterwards by machining.

Further, the second welding step is performed. In this step the rootgap, after forming of the root layer, is filled by performing fillerweld. The ‘root gap’ after forming of the root layer technicallyhereinafter referred to as a ‘gap.’ This gap is filled by repeatedlydepositing filler weld electrodes. While performing the filler weldthere are very likely chances of the root layer obtained in the firststep of getting pressed out due the heat transfer effect of the fillerweld. Generally, while performing the filler weld, compression stress onthe root weld may be created, and therefore, there are likely chancesthat the root layer may plastically deform, which may lead to pressingout of the weld materials, such as the root weld or filler weldmaterials. Such pressing out of the weld material may reduce the life ofthe welded conduits due to corrosions as mentioned. Therefore in orderto reduce such chances, generally machining of the deposited weldmaterial are done wherein the excess root material are removed bymachining manually or by utilizing any automatic device. Such machiningis time consuming and cumbersome process that requires a lot of hands inturn increasing the costing over all of the welded conduits.

Accordingly, there exists a need of time effective, economic and handyways for preventing deposition of the root weld in and around thewelding zone of the conduit's inner surfaces, which precludes therequired machining to remove the deposited root weld.

SUMMARY

In view of the forgoing disadvantages inherent in the prior-art, thepresent disclosure provides method and system for welding conduits. Suchmethod and system is configured to include all advantages of the priorart, and to overcome the drawbacks inherent in the prior art and providesome additional advantages.

An object of the present disclosure is to provide time effective,economic and handy ways for preventing deposition of weld material inand around welding zone of the conduit's inner surfaces while weldingthe conduits.

Another object of the present disclosure is to preclude the requirementof machining to remove deposited weld materials.

To achieve the above objects, in an aspect of the present disclosure, amethod for welding two or more conduit members is provided. The methodcomprising:

aligning two or more end portions of the two or more conduit members inan abutting relationship to define a gap, the conduit members havingouter and inner opposite circumferential surfaces sides;

performing a root weld along the gap from the outer circumferentialsurfaces side to configure a root layer, in a manner that preventsspattering of the root weld material along the inner circumferentialsurfaces side;

applying an outward thrust, along the inner circumferential surfacesside; and

performing a filler weld along the gap from the outer circumferentialsurfaces side thereof to fill the gap,

performances of the filler weld upon the application of the outwardthrust ensures shrinkage of the filler and root weld materialslongitudinally and radially outward, across the two or more conduitmembers, preventing pressing out of the filler and root weld materialsalong the inner circumferential surfaces side while performing thefiller weld.

In one embodiment of the above aspect the method further comprisingpreparing edges of the two or more end portions of the two or moreconduit members for performing the root weld.

In one embodiment of the above aspect applying the outward thrustfurther comprises, providing a support member along the innercircumferential surfaces side; and actuating the support member toexpand diametrically along the inner circumferential surfaces of the twoor more conduits for applying the outward thrust.

In one embodiment of the above aspect, the method comprising releasingthe upward thrust upon solidifying of the filler and root weldmaterials.

In one embodiment, the support member is actuated and released byutilizing one of a hydraulically, a pneumatically, a mechanically or athermally actuating arrangement.

In another aspect of the present disclosure, a system for welding two ormore conduit members is provided. The system comprises:

a root welding tool to root weld a gap to form a root layer in the gapconfigured along two or more end portions of the two or more conduitmembers aligned in an abutting relationship, from an outercircumferential surfaces side, opposite to an inner circumferentialsurfaces side, of the two or more conduit members, the root weldperformed in a manner that prevents spattering of the root weld materialalong the inner circumferential surfaces side;

a filler welding tool to filler weld the gap from the outercircumferential surfaces side to fill the gap; and

a support member provided along the inner circumferential surfaces sidefor applying an outward thrust therealong to ensure shrinkage of thefiller and root weld materials longitudinally and radially outward,across the two or more conduit members, thereby preventing pressing outof the filler and root weld materials along the inner circumferentialsurfaces while performing the filler weld.

In one embodiment of the above aspect, the system further comprises anedge preparation tool for preparing edges of the two or more endportions of the two or more conduit members to perform the root weld.

In one embodiment of the above aspect, the support member comprises, anactuating arrangement capable of being actuated to expand diametricallyalong the inner circumferential surfaces of the two or more conduits forapplying the outward thrust; and a releasing arrangement configured inconjunction with the actuating arrangement, the releasing arrangementcapable of releasing the upward thrust upon solidifying of the fillerand root weld materials.

In one embodiment, the actuating and the releasing arrangements of thesupport member are one of a hydraulically, a pneumatically, amechanically or a thermally operated arrangements.

The above aspects of the present disclosure are capable providing timeeffective, economic and handy ways for preventing deposition of weldmaterial in and around welding zone of the two or more conduit's innersurfaces while welding and thereafter.

Specifically, the support member of the present disclosure is providedto prevent the deposition of the weld materials which in turn precludesthe requirement of machining. The support member is provided along theinner circumferential surfaces side for applying the outward thrusttherealong to ensure shrinkage of the filler and root weld materialslongitudinally and radially outward, across the two or more conduitmembers. This prevents pressing out of the filler and root weldmaterials along the inner circumferential surfaces while performing thefiller weld, and till solidifying of the weld material. Further, theoutward thrusts provided by the support member also manage to ensure thestress development across the two or more conduit members inlongitudinally and radially outward direction. This enables thedurability of the weld and prevents any type of cracking in the weldwhile and after its formation.

The term ‘welding zone’ used herein is a zone where the welding, such asthe root weld or the filler weld is performed. The welding zone is inand around the gap.

The terms ‘inner circumferential surfaces side’, and ‘outercircumferential surfaces side’ respectively, used herein refer to, innerside of the conduits or inner surfaces of the conduits, and outer sideof the conduits or outer surfaces of conduits.

These together with the other aspects of the present disclosure, alongwith the various features of novelty that characterized the presentdisclosure, are pointed out with particularity in the claims annexedhereto and form a part of the present disclosure. For a betterunderstanding of the present disclosure, its operating advantages, andthe specified object attained by its uses, reference should be made tothe accompanying drawings and descriptive matter in which there areillustrated exemplary embodiments of the present disclosure.

BRIEF DESCRIPTION OF THE DRAWINGS

The advantages and features of the present disclosure will betterunderstood with reference to the following detailed description andclaims taken in conjunction with the accompanying drawing, wherein likeelements are identified with like symbols, and in which:

FIG. 1 illustrates a block diagram of a system for welding two or moreconduits, in accordance with an exemplary embodiment of the presentdisclosure;

FIGS. 2A to 2D illustrate block diagrams depicting welding of the two ormore conduits, in accordance with an exemplary embodiment of the presentdisclosure; and

FIG. 3 illustrates a flow chart of a method for welding the two or moreconduits, in accordance with an exemplary embodiment of the presentdisclosure.

Like reference numerals refer to like parts throughout the descriptionof several views of the drawings.

DETAILED DESCRIPTION

For a thorough understanding of the present disclosure, reference is tobe made to the following detailed description, including the appendedclaims, in connection with the above- described drawings. Although thepresent disclosure is described in connection with exemplaryembodiments, the present disclosure is not intended to be limited to thespecific forms set forth herein. It is understood that various omissionsand substitutions of equivalents are contemplated as circumstances maysuggest or render expedient, but these are intended to cover theapplication or implementation without departing from the spirit or scopeof the claims of the present disclosure. Also, it is to be understoodthat the phraseology and terminology used herein is for the purpose ofdescription and should not be regarded as limiting. Further, the term“one embodiment,” “another embodiment,” “various embodiments,” and thelike used herein is for the purpose of description and should not beregarded as limiting to the particular embodiment.

The term “first,” “second,” “inner,” “outer” and the like, herein do notdenote any order, elevation or importance, but rather are used todistinguish one element over another. Further, the terms “a,” “an,” and“plurality” herein do not denote a limitation of quantity, but ratherdenote the presence of at least one of the referenced item.

Referring now to FIG. land FIGS. 2A to 20, depicting a system 100, forwelding two or more conduits, in accordance with various exemplaryembodiments of the present disclosure are illustrated. The system 100includes a root welding tool 110, a filler welding tool 120 and asupport member 130 utilized for creating an environment for welding twoor more conduits. For the purpose of description of the presentembodiment of the disclosure two conduit members, such as a firstconduit member 200 and a second conduit member 300, (hereinafter alsoreferred to as conduits 200 and 300) are illustrated in FIG. 1, withoutlimiting its scope to include any required numbers of the conduits.

As shown in FIG. 2A, the first and second conduits 200 and 300 arealigned in an abutting relationship, at a predetermined distance, to oneanother for a butt type of welding without a backing ring. Specifically,an end portion 210 of the conduit 200 and an end portion 310 of theconduit 300 are aligned in a manner facing each other. The conduits 200and 300, respectively, include outer circumferential surfaces 220 and320 (referred to as outer surfaces side 220, 320), and innercircumferential surfaces 230 and 330 (referred to as -inner surfacesside 230, 330) opposite to each other. As shown in FIGS. 2A and 2Bduring the root welding, the inner ring surface sides 230 and 330 arefree of any obstructions such as a backing ring. The conduits 200 and300 may be coupled to a clamping, driving and holding devices, as knownin the art. Such devices engage the conduits 200 and 300, either fromthe outer surfaces side 220, 320 or from the inner surfaces side 230,330 thereof, to drive thereto towards each other, such that respectiveend portions 210 and 310 faces each other. In one embodiment, the edgesof the end portions 210 and 310 are prepared, such as chamfered orbeveled, in opposite directions to complement each other, prior toaligning the conduits 200 and 300. Such preparation of the end portions210 and 310 configures to a gap 400 between the end portions 210 and 310of the two adjacent conduits 200 and 300. The edges preparation may beperformed as per the requirement of the conduits 200 and 300 toconfigure the gap 400 of shapes including, but not limited to, V-shape,J-shape, and the like, by utilizing an edge preparation tool 150, suchas chamfering tools, as illustrated in FIG. 2A. Such edge preparation ofthe conduits 200, 300 defines a root gap along the gap 400 near to theinner circumferential surfaces 230, 330 of the conduits 200, 300. Suchdevices, upon making contact with the conduits 200 and 300, bindmovements towards each other to lock thereto in a position to preventone conduit from separating or moving back away from other conduit. Theclamps which grasp the conduits 200 and 300 may be designed to graspthereto from the outer surfaces sides 220, 320 or from the innersurfaces side 230, 330, whichever is most convenient.

Further, in the system 100, the root welding tool 110 is configured toroot weld the gap 400 to form a root layer 410 in the root gap 400. The‘gap 400’ before forming of the ‘root layer 410’ technically defines theroot gap, as it is generally referred in the technical filed of conduitswelding, wherein the root layer 410 is formed, and may also hereinafterrefer to as a ‘root gap 400,’ to distinguish the welding process. Theroot welding tool 110 may be electrically actuated and controlled toperform its desired purpose via utilizing an electrical control panel140. However, the provision of having the electrical control panel 140in the system 100 does not exclude the scopes of enabling the entirewelding process manually. The root welding tool 110 includes weldingarrangements that is capable of holding and processing electrodes, forexample bare or uncoated electrodes, for forming the root layer 410 inthe root gap 400. The root welding tool 110 with the electrodes isprovided from the outer surfaces side 220, 320 of the conduits 200, 300for depositing the molten electrode weld material within the root gap400 for configure the root layer 410. The root weld for configuring theroot layer 410 is performed without a backing ring and in a manner thatprevents spattering of the root weld material along the inner surfacesside 230, 330 of the conduits 200, 300. The root layer, withoutspattering of the root weld material along the inner surfaces side 230,330 of the conduits 200, 300, may be performed by using various moderntechnologies and process, such as automatic welding, gas tungsten arcwelding, electronic beam welding and laser beam welding, etc.

Further, in the system 100, the filler welding tool 120 is configured tofiller weld the gap 400, above the root layer 410, from the outersurfaces side 220, 320 of the conduits 200, 300 to fill the gap 400. Thefiller welding tool 120 may also be electrically actuated and controlledto perform its desired purpose via utilizing the electrical controlpanel 140, without departing the provision of enabling the entirewelding process manually. The filler welding tool 120 includes weldingarrangements that is capable of holding and processing fillerelectrodes, for example coated electrodes, for forming filler layers 420in the gap 400. The root welding tool 110 with the filler electrodes isprovided from the outer surfaces side 220, 320 of the conduits 200, 300for depositing the molten filler electrode weld material within the gap400. This process is repeated continuously until the gap 400 filledcompletely configuring the filler layers 420, and in turn welding theconduits 200, 300. The filler weld for configuring the filler layers 420is performed in a manner that prevents pressing out of the weldmaterials along the inner surfaces side 230, 330 of the conduits 200,300. Generally, while performing the filler weld, the filler layers 420create compression stress on the root weld, and therefore, there arelikely chances that the root layer 410 may plastically deform, which maylead to pressing out of the weld materials, such as the root weld orfiller weld materials. This is where the present disclosure provides themost preferred embodiment to prevent such pressing out of the weldmaterials.

In the most preferred embodiment of the present disclosure, the supportmember 130 is provided. The support member 130 is inserted within theconduits 200, 300, for supporting the inner surfaces side 230, 330thereof. The support member 130 is capable of applying an outward thrust(as shown by arrows set ‘A’) along the inner surfaces side 230, 330 toensure shrinkage of the filler and root weld materials longitudinallyand radially outward (as shown by arrow set ‘B’), across the two or moreconduits 200, 300. For example, the upward thrust may vary between about100 bars to about 500 bars. However, without departing from the scope ofthe present disclosure, the support member 130 is capable of providingany required upward thrust upon the requirement. The support member 130is capable of providing support during the filler weld process and untilthe solidifying of the complete weld material, which in turn preventpressing out of the weld materials along the inner surfaces side 230,330. In one form, the support member 130 may be inserted within theconduit 200, 300 and applies the upwards thrust, prior to performing thefiller welding process, i.e. after the root weld is finished. In otherform, the support member 130 may also be inserted within the conduit200, 300 and apply the upwards thrust simultaneously while performingthe filler welding process. Further, the outward thrusts provided by thesupport member 130 also manage to ensure the stress development acrossthe conduits 200, 300 in longitudinally and radially outward direction(as 10 shown by arrow set ‘B’). This enables the durability of the weldand prevents any type of cracking in the weld while and after itsformation. The support member 130 may be electrically actuated andcontrolled to perform its desired purpose via utilizing the electricalcontrol panel 140. However, the provision of having the electricalcontrol panel 140 in the system 100 does not exclude the scopes ofenabling the support member 130 manually.

In one embodiment of the present disclosure, the support member 130 mayinclude an actuating arrangement 132 and an releasing arrangement 134configured in conjunction to each other and with the support member 130for enabling the application of the outward thrust, and releasingthereof. Upon inserting the support member 130 within the conduits 200,300, the actuating arrangement 132 is capable of being actuated toexpand diametrically the support member 130 along the inner surfaces230, 330 of the conduits 200, 300. Such expansion exerts the outwardthrust to ensure shrinkage of the filler and root weld materialslongitudinally and radially outward from the inner surfaces side 230,330, across the conduits 200, 300. This outward thrust prevents pressingout of the weld materials along inner surfaces side 230, 330. Once thefiller welding is complete and the welded material is solidified, the 25releasing arrangement 134 is capable of releasing the upward thrust. Theactuating and releasing arrangements 132, 134 may be activatedelectrically by the help of the electrical control panel 140 or may bemanually activated.

In various embodiments of the present disclosure, the support member 130may be one of a hydraulically, a pneumatically, a mechanically or athermally operated support member for enabling the application of theoutward thrust, and releasing thereof. In various embodiments of thepresent disclosure, actuating and releasing arrangements 132, 134 may beone of a hydraulically, a pneumatically, a mechanically or a thermallyoperated arrangements for enabling the application of the outwardthrust, and releasing thereof.

In hydraulic and pneumatic configurations, respectively, hydraulic andpneumatic forces are applied and released to provide the upward thrustwith the help of the actuating and releasing arrangements 132, 134 inconjunction of the support member 130. Further, in mechanicalconfiguration, the upward thrust may be applied by mechanicallyactivating the actuating and releasing arrangements 132, 134 inconjunction to the support member 130. Furthermore, in thermalconfiguration, the upward thrust may be applied by thermally activatingthe actuating and releasing arrangements 132, 134 in conjunction of thesupport member 130.

Welding of the conduits 200, 300 by providing the support member 130from the ‘inside support surface’ may develop stress in the weldingzone, therefore, in order to release such stress in the cost effectivemanner, the post weld heat treating may be carried out afterwards.

Referring now to FIG. 3, a flow chart of a method 600 for welding thetwo or more conduits, such as the conduits 200, 300, in accordance withan exemplary embodiment of the present disclosure is illustrated. Themethod 600 will be described herein in conjunction with the system 100as shown in FIGS. land 2A to 20. The method 600 starts at 610. Furtherat 620, the conduits 200 and 300 are aligned in an abutting relationshipat a predetermined distance to define a root gap, such as the root gap400, as explained above. In one embodiment of the present disclosure,the conduits' end portions 210, 310 may be prepared by chamfering inopposite directions to complement each other, prior to aligning theconduits 200 and 300, as explained herein above, and excluded herein forthe sake of brevity.

At 630, a root weld along the root gap 400 from outer circumferentialsurfaces side, such as the outer surfaces side 220, 320, is performed toconfigure a root layer, such as the root layer 410, by utilizing a rootwelding tool, such as the root welding tool 110, as explained above andexcluded herein for the sake of brevity. The root weld is performed insuch a manner that prevents spattering of the root weld material alongthe inner circumferential surfaces side, such as the inner surfaces side230, 330.

At 640, an outward thrust along the inner surfaces side 230, 330 isapplied.

Furthermore at 650, filler weld of the gap 400, above the root layer410, from the outer surfaces side 220, 320 of the conduits 200, 300 tofill the gap 400 is performed by utilizing a welding tool, such as thefiller welding tool 120, as explained above and excluded herein for thesake of brevity.

In one form, the support member 130 may be inserted within the conduit200, 300 and applies the upwards thrust, prior to performing the fillerwelding process, i.e. after the root weld is finished. In other form,the support member 130 may also be inserted within the conduit 200, 300and apply the upwards thrust simultaneously while performing the fillerwelding process, without departing from the scope of the presentdisclosure.

The outward thrust along the inner surfaces side 230, 330 is applied toensure shrinkage of the weld materials, such as such as the root weld orfiller weld materials, longitudinally and radially outward, across theconduits 200, 300. In turn, this prevents pressing out of the filler androot weld materials along the inner circumferential surfaces side 230,330, while performing the filler weld, and until solidifying of the weldmaterials. In one embodiment of the present disclosure, the upwardthrust is provided by utilizing a support member, such as the supportmember 130, along the inner surfaces side 230, 330, and actuating thesupport member 130 to expand diametrically along the inner surfaces side230, 330. The detailed explanation thereof is excluded herein for thesake of brevity.

In one embodiment of the present disclosure, the support member 130 mayinclude an actuating arrangement, such as the actuating arrangement 132,and an releasing arrangement, such as the releasing arrangement 134,configured in conjunction to each other and with the support member 130for enabling the application of the outward thrust, and releasingthereof. The same has been explained herein above and excluded hereinfor the sake of brevity. The method 600 stops at 660.

The system 100 and the method 600 of the present disclosure offerfollowing advantages. The system and method are capable providing timeeffective, economic and handy ways for preventing deposition or pressingout of weld material in and around welding zone of the two or moreconduit's inner surfaces while welding. Specifically, the support memberof the present disclosure is provided to prevent the deposition orpressing out of the weld materials which in turn precludes therequirement of machining. The support member is provided along the innercircumferential surfaces side for applying the outward thrust therealongto ensure shrinkage of the filler and root weld materials longitudinallyand radially outward, across the two or more conduit members. Thisprevents deposition or pressing out of the weld materials along theinner circumferential surfaces while performing the filler weld.Further, the outward thrusts provided by the support member also manageto ensure the stress development across the two or more conduit membersin longitudinally and radially outward direction. This enables thedurability of the weld and prevents any type of cracking in the weldwhile and after its formation.

The foregoing descriptions of specific embodiments of the presentdisclosure have been presented for purposes of illustration anddescription. They are not intended to be exhaustive or to limit thepresent disclosure to the precise forms disclosed, and obviously manymodifications and variations are possible in light of the above teachingThe embodiments were chosen and described in order to best explain theprinciples of the present disclosure and its practical application, tothereby enable others skilled in the cover the application orimplementation without departing from the spirit or scope of the claimsof the present disclosure.

What is claimed is:
 1. A method for welding two or more conduit members,the method comprising: aligning two or more end portions of the two ormore conduit members in an abutting relationship to define a gap, theconduit members having an outer circumferential surface side and aninner circumferential surface side; having the inner circumferentialsurface side unobstructed; performing a root weld along the gap from theouter circumferential surface side to configure a root layer while theinner circumferential surface side is unobstructed, the root weld beingperformed in a manner that prevents spattering of the root weld materialalong the inner circumferential surface side; after the root weld iscomplete, applying an outward thrust along the inner circumferentialsurface side; and during application of the outward thrust, performing afiller weld along the gap from the outer circumferential surface sidethereof to fill the gap so as to facilitate shrinkage of the filler androot weld materials longitudinally and radially outwardly whilepreventing pressing out of the filler and root weld materials radiallyinwardly of the inner circumferential surface side.
 2. The method forwelding the two or more conduit members as claimed in claim 1, furthercomprising preparing edges of the two or more end portions of the two ormore conduit members for performing the root weld.
 3. The method forwelding the two or more conduit members as claimed in claim 1, whereinapplying the outward thrust further comprises, providing a supportmember along the inner circumferential surface side after the root weldis complete; and actuating the support member to expand diametricallyalong the inner circumferential surface side of the two or more conduitsfor applying the outward thrust.
 4. The method for welding the two ormore conduit members as claimed in claim 3, wherein actuating thesupport member by one of a hydraulically, a pneumatically, amechanically or a thermally actuating arrangement.
 5. The method forwelding the two or more conduit members as claimed in claim 1, furthercomprising releasing the upward thrust upon solidifying of the fillerand root weld materials.
 6. The method for welding the two or moreconduit members as claimed in claim 5, wherein releasing the upwardthrust by one of a hydraulically, a pneumatically, a mechanically or athermally releasing arrangement.
 7. The method for welding the two ormore conduit members as claimed in claim 1, wherein the applying anoutward thrust along the inner circumferential surface side is donesimultaneously with the performing the filler weld.
 8. The method forwelding the two or more conduit members as claimed in claim 3, whereinthe providing the support member is done simultaneously with theperforming the filler weld.
 9. The method for welding the two or moreconduit members as claimed in claim 1, wherein the outward thrust isprovided across the two or more conduit members.
 10. The method forwelding the two or more conduit members as claimed in claim 1, whereinthe outward thrust is provided across the root weld.